---
name: "set_display_switch_callback"
section: "3alleg"
platform: "linux"
package: "liballegro-doc"
version: "2:4.2.2-2.2"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/set_display_switch_callback"
---

# set\_display\_switch\_callback(3alleg)

Installs a switching notification callback. Allegro game programming library.

## NAME

set\_display\_switch\_callback - Installs a switching notification callback. Allegro game programming library.

## SYNOPSIS

**#include \<allegro.h\>**

**int set\_display\_switch\_callback(int dir, void (\*cb)());**

## DESCRIPTION

Installs a notification callback for the switching mode that was  previously selected by calling set\_display\_switch\_mode(). The direction  parameter can either be SWITCH\_IN or SWITCH\_OUT, depending whether you  want to be notified about switches away from your program or back to your  program. You can sometimes install callbacks for both directions at the  same time, but not every platform supports this. You can install several switch callbacks, but no more than eight on any platform.

## RETURN VALUE

Returns zero on success, decreasing the number of empty callback slots by one. Returns -1 if the request is impossible for the current platform or you have reached the maximum number of allowed callbacks.

## SEE ALSO

[**remove\_display\_switch\_callback**(3alleg)](/remove_display_switch_callback/3alleg.md), [**set\_display\_switch\_mode**(3alleg)](/set_display_switch_mode/3alleg.md), [**exswitch**(3alleg)](/exswitch/3alleg.md)